Body attacks itself. In autoimmune disease your immune system attacks your own body. This causes serious problems like colitis, thyroiditis, multiple sclerosis & lupus. There are often genetic predispositions but there is growing evidence that microbes and environmental toxins such as molds, heavy metals & pesticides play a key role. A well-written book on this is http://www.Donnajacksonnakazawa.Com/blog/?Page_id=7.

Self appears foreign. The body's immune system is designed to protect the body from foreign invaders like bacteria or unknown proteins. The body produces anti-bodies to fight the invading agent. In autoimmune conditions the body mistakenly produces anti-bodies to itself. When these self-antibodies attack the proteins they are directed against an inflammatory reaction occurs. The reaction causes symptoms like rashes.